The Internet provides a vast amount of information, which may be stored at many different sites and on many different devices, such as on servers and clients or in databases, around the world. These different devices at the different sites are communicatively linked to computer or communication networks over wire-line or wireless connections. A person may access specific pieces of information available on the Internet using a suitable network device (e.g., a computer, a smart mobile telephone, an entertainment console, etc.) connected to a network.
Due to the sheer amount of information available on the Internet, it is impractical as well as impossible for a person (e.g., a network user) to manually search throughout the Internet for the specific pieces of information he needs. Instead, most network users rely on different types of computer-implemented tools to help them locate the desired information. One of the most commonly and widely used computer-implemented tools is a search tool, also referred to as a search engine. To search for information relating to a specific topic on the Internet, a user typically provides a few words, often referred to as a “search query” or simply “query”, describing the topic to a search tool. The search tool conducts a search based on the search query using various search algorithms and generates a set of search results, each corresponding to some information that is most likely to be related to the search query. The search results are then presented to the user.
Sophisticated search tools implement many other functionalities in addition to merely identifying the search results as a part of the search process. For example, a search tool usually ranks the identified search results according to their relative degrees of relevance with respect to the search query, such that the search results that are relatively more relevant to the search query are ranked higher than and consequently are presented to the network user before the search results that are relatively less relevant to the search query. There are continuous efforts to improve the quality of the search results generated by the search tools.